Cooling system having anti-recirculation feature

ABSTRACT

A cooling system is disclosed for use with an engine. The cooling system may have a heat exchanger fluidly connectable to the engine, and a fan situated adjacent the heat exchanger and configured to generate a flow of air through the heat exchanger. The cooling system may also include an anti-recirculation feature located adjacent the fan and configured to block the flow of air at a center of the fan and allow air to flow at a periphery of the fan.

TECHNICAL FIELD

The present disclosure relates generally to a cooling system and, more particularly, to a cooling system having an anti-recirculation feature configured to enhance engine cooling.

BACKGROUND

Most mobile machines are powered by an internal combustion engine, for example a diesel engine, a gasoline engine, or a gaseous-fuel powered engine. Each of these engines combust a mixture of fuel and air to generate a mechanical power output used to propel the machine. With the purpose to ensure optimum combustion of the fuel/air mixture and protect components of the engine from damaging extremes, temperature of the engine and air drawn into the engine for combustion should be tightly controlled.

Typical internal combustion engines are cooled by way of a heat exchanger and an axial cooling fan disposed adjacent (e.g. in front of or behind) the heat exchanger. Coolant from the engine is circulated through the heat exchanger, while the axial cooling fan directs a flow of fresh air through the heat exchanger to absorb heat from the coolant. The coolant, having dissipated heat to the air, is then circulated back through the engine to cool the engine. The air, after having absorbed heat from the heat exchanger, is directed to the atmosphere.

Unfortunately, not all of the air directed by the fan through the heat exchanger is fresh and cool and capable of adequately absorbing significant amounts of heat from the engine. In particular, conventional cooling fans generate a flow of air having a higher pressure at an outer periphery than at an axial center. In some situations, this pressure gradient can cause some of the higher pressure air at the outer periphery to reverse direction after passing through the heat exchanger and be drawn back through the lower pressure center of the heat exchanger. This recirculated air has an elevated temperature that can reduce an efficiency of the heat exchanger.

An attempt to address one or more of the problems described above is disclosed in U.S. Pat. No. 5,180,003 that issued to Kouzel et al. on Jan. 19, 1993 (the '003 patent). Specifically, the '003 patent describes a cooling system having a dual-fan architecture, including a primary fan and a smaller secondary fan. The primary fan is disposed at one side of a heat exchanger to push air through the heat exchanger, while the smaller secondary fan is disposed at an opposing side of the heat exchanger to pull air through the heat exchanger. The smaller secondary fan is located at an area of lowest air flow at a center of the primary fan and is intended to eliminate recirculation of air back through the heat exchanger.

Although the dual-fan architecture of the '003 patent may help to reduce air recirculation through the heat exchanger, it may also be complicated, expensive, and difficult to package. In addition, the added fan and associated mounting and control components may decrease a reliability of the cooling system.

The cooling system is directed to overcoming one or more of the problems set forth above and/or other problems of the prior art.

SUMMARY

In one aspect, the present disclosure is directed to a cooling system. The cooling system may include a heat exchanger fluidly connectable to the engine, and a fan situated adjacent the heat exchanger and configured to generate a flow of air through the heat exchanger. The cooling system may also include an anti-recirculation feature located adjacent the fan and configured to block the flow of air at a center of the fan and allow air to flow at a periphery of the fan.

In another aspect, the present disclosure is directed to an engine grill. The engine grill may include an end portion, and a plurality of perforations formed within the end portion in a pattern around a middle of the end portion. The engine grill may also include an anti-recirculation feature situated at the middle of the end portion within the pattern of the plurality of perforations.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a pictorial illustration of an exemplary disclosed machine; and

FIG. 2 is a pictorial illustration of an exemplary disclosed cooling system that may be used in conjunction with the machine of FIG. 1; and

FIG. 3 is a pictorial illustration of an exemplary disclosed engine grill associated with the cooling system of FIG. 2.

DETAILED DESCRIPTION

FIG. 1 illustrates an exemplary embodiment of a machine 10. Machine 10 may be a stationary or mobile machine that performs some type of operation associated with an industry such as mining, construction, farming, transportation, petroleum, or another industry known in the art. For example, machine 10 may be an earth moving machine such as the motor grader shown in FIG. 1, a wheel loader, a track-type tractor, a haul truck, or another type of mobile machine. Alternatively, machine 10 may be associated with electric power generation, fluid (e.g., oil, water, gas, etc.) pumping, or another stationary application, if desired. In the disclosed embodiment, machine 10 may include a frame 12 that supports an engine 14 within an enclosure 16. Enclosure 16 may include, among other things, a housing 18 and a removable cowling 20 that closes off an end of housing 18. Housing 18 may be provided with one or more air inlets 22 configured to allow air flow through at least a portion of enclosure 16 for cooling purposes, as will be described in more detail below.

As shown in FIG. 2, machine 10 may be equipped with a cooling system 24 that communicates with air inlets 22 to facilitate the production of power within engine 14. Cooling system 24 may include, among other things, a heat exchanger 26 disposed within housing 18 and fluidly connected to engine 14, and a fan 28 disposed within housing 18 adjacent heat exchanger 26. Heat exchanger 26 may embody the main radiator of engine 14 and be situated to dissipate heat from the coolant after it passes through engine 14. As the main radiator of engine 14, heat exchanger 26 may be a liquid-to-air type of exchanger. That is, a flow of air may be directed from air inlets 22 through channels of heat exchanger 26 such that heat from coolant within adjacent channels is transferred to the air. In this manner, the coolant passing through engine 14 may be cooled to below a predetermined operating temperature of engine 14. Cooling fan 28 may situated to generate the flow of air directed through heat exchanger 26.

In the disclosed embodiment, fan 28 may be located between heat exchanger 26 and cowling 20 to draw air from inlets 22 of housing 18 through heat exchanger 26, and push the air out through and end of cowling 20. Fan 28 may include, among other things, a hub 30 and a plurality of inclined blades 32 that extend radially outward from hub 30. Fan 28 may be driven by engine 14 directly (e.g., via a mechanical connection such as a pulley or gear drive) or indirectly (e.g., via a hydraulic or electric motor 34), and include mounting hardware 36 configured to fixedly connect fan 28 to engine cowling 20. Fan 28 may also be pivotally connected to heat exchanger 26 (e.g., at a lower edge of heat exchanger 26) such that fan 28 and heat exchanger 26 may together form a door to enclosure 16 (referring to FIG. 1) that can be selectively opened during servicing to provide access to fins of heat exchanger 26. In this configuration, a handle 38 located at an upper edge of cowling 20 may provide for manual locking and releasing of fan 28 and cowling 20 relative to heat exchanger 26. It is contemplated that fan 28 may alternatively be mounted at an opposing side of heat-exchanger 26 relative to cowling 20 (i.e., between engine 14 and heat exchanger 26), if desired. In this alternative configuration, fan 28 may push air through heat exchanger 26 rather than pull air through heat exchanger 26.

Cowling 20 may include an engine grill 40 located at an end thereof. Engine grill 40 may be configured to allow the air flow generated by fan 28 to pass through cowling 20, while simultaneously inhibiting passage of debris larger than a certain size. In particular, as shown in FIG. 3, engine grill 40 may include a plurality of perforations 42 disposed in a pattern around a generally solid disc-shaped anti-recirculation feature 44 that is positioned concentric with fan 28 (at a general mid of engine grill 40—referring to FIG. 2). In the disclosed embodiment, perforations 42 may be arranged in a honeycomb configuration with a cross-sectional area of each perforation and/or density of perforations 42 being selected based on an intended application of machine 10. It should be noted that perforation configurations other than honeycomb may be utilized, if desired. Engine grill 40, including anti-recirculation feature 44 may be made from any material known in the art, for example from a corrosion and/or heat resistant material or from another material that is coated in a corrosion and/or heat resistant coating.

Engine grill 40 may include a generally planar first portion 46 and a generally planar second portion 48 that is located below first portion 46 (i.e., between first portion 46 and frame 12). As shown in FIGS. 1 and 2, first portion 46, when assembled within cowling 20, may be inclined outward from an upper edge toward second portion 48. Second portion 48 may be tilted inward at a lower edge, away from first portion 46 and toward fan 28 and heat exchanger 26, such that an intersection of first and second portions 46, 48 is located furthest away from fan 28. Returning to FIG. 3, a plurality of transverse corrugations 50 may be formed within first and second portions 46 to increase a rigidity of engine grill 40. Anti-recirculation feature 44 may be formed at least partly within both of first and second portions 46, 48, and corrugations 50 may pass through anti-recirculation feature 44. Engine grill 40, including anti-recirculation feature 44, perforations 42, and corrugations 50, may be fabricated from any suitable material (e.g., steel) as a single integral component through, for example, conventional stamping and punching operations. It is contemplated, however, that anti-recirculation feature 44 may alternatively be fabricated as a stand-alone disc-shaped component that can be subsequently assembled adjacent to and/or joined with engine grill 40, if desired.

Anti-recirculation feature 44 may be designed to enhance performance of cooling system 24. In particular, anti-recirculation feature 44 may have geometry and be located to inhibit recirculation of warm air through heat exchanger 26. Specifically, anti-recirculation feature 44 may have an outer diameter D1 greater than an outer diameter D2 of hub 30 (referring to FIG. 2), but less than an outer diameter D3 of blades 32. It has been found that as the outer diameter D1 of anti-recirculation feature 44 approaches the outer diameter D2 of hub 30, a greater amount of the air flow generated by fan 28 may be recirculated through heat exchanger 26. In contrast, it has also been found that as the outer diameter D1 of anti-recirculation feature 44 approaches the outer diameter D3 of blades 32, a lower amount of the air flow generated by fan 28 may pass through cowling 20 and a restriction on the air flow may increase. When the outer diameter D1 of anti-recirculation feature 44 is about 60-80% of the outer diameter D3 of blades 32, a desired amount of the air flow generated by fan 28 may pass through cowling 20 with a negligible amount of the air flow being recirculated back through heat exchanger 26. In the disclosed embodiment, diameter D3 may be about 550-600 mm.

INDUSTRIAL APPLICABILITY

The disclosed cooling system, together with engine 14, may form a power unit applicable to any mobile or stationary machine where efficient engine cooling is desired. The disclosed cooling system may improve cooling efficiency by reducing an amount of air that is recirculated through an associated heat exchanger. The disclosed cooling system may employ anti-recirculation feature 44 to reduce the amount of recirculated air. In particular, anti-recirculation feature 44 may block higher pressure air flow from the outer periphery of fan 28 from being drawn back through a lower pressure center of fan 28 and heat exchanger 26. In this manner, a greater amount of cool fresh air may pass through heat exchanger 26, thereby increasing an amount of cooling and an associated efficiency of heat exchanger 26. In fact, it has been demonstrated that anti-recirculation feature 44 may actually increase airflow through heat exchanger 26 by 5% or more. Noise reduction has also been shown to occur through the use of anti-recirculation feature 44.

It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed cooling system without departing from the scope of the disclosure. Other embodiments of the cooling system will be apparent to those skilled in the art from consideration of the specification and practice of the thermal management system disclosed herein. For example, in an alternative configuration described above, where fan 28 is located between engine 14 and heat exchanger 26 in opposition to engine cowling 20, it is contemplated that anti-recirculation feature 44 may be a stand-alone component (i.e., separate from engine grill 40) and located adjacent fan 28 at an upstream or downstream side of fan 28. It is intended that the specification and examples be considered as exemplary only, with a true scope of the disclosure being indicated by the following claims and their equivalents. 

What is claimed is:
 1. A cooling system for an engine, comprising: a heat exchanger fluidly connectable to the engine; a fan situated adjacent the heat exchanger and configured to generate a flow of air through the heat exchanger; and an anti-recirculation feature located adjacent the fan and configured to block the flow of air at a center of the fan and allow air to flow at a periphery of the fan.
 2. The cooling system of claim 1, wherein the anti-recirculation feature includes a generally disc-shaped solid member.
 3. The cooling system of claim 2, wherein: the fan includes: a hub; and a plurality of fan blades extending radially outward from the hub; and the anti-recirculation feature has an outer diameter greater than an outer diameter of the hub and smaller than an outer diameter of the plurality of fan blades.
 4. The cooling system of claim 3, wherein the outer diameter of the anti-recirculation feature is about 60-80% of the outer diameter of the plurality of fan blades.
 5. The cooling system of claim 3, wherein the outer diameter of the anti-recirculation feature is about 550-600 mm.
 6. The cooling system of claim 2, wherein the anti-recirculation feature is an integral portion of an engine grill and disposed opposite the heat exchanger relative to the fan.
 7. The cooling system of claim 6, wherein the engine grill includes a plurality of perforations formed in a pattern around the anti-recirculation feature.
 8. The cooling system of claim 7, wherein the plurality of perforations extend from an outer diameter of the anti-recirculation feature past an outer diameter of blades of the fan.
 9. The cooling system of claim 6, wherein: the engine grill includes: a generally planar first portion; and a generally planar second portion tilted inward from the first portion toward the fan; and the anti-recirculation feature extends at least partway across the first and second portions.
 10. The cooling system of claim 9, wherein the engine grill includes a plurality of transverse corrugations that extend across the anti-recirculation feature.
 11. The cooling system of claim 6, further including a cowling configured to connect the engine grill to the fan.
 12. An engine grill, comprising: an end portion; a plurality of perforations formed within the end portion in a pattern around a middle of the end portion; and an anti-recirculation feature situated at a middle of the end portion within the pattern of the plurality of perforations.
 13. The engine grill of claim 12, wherein the anti-recirculation feature is a generally disc-shaped solid member.
 14. The engine grill of claim 13, wherein an outer diameter of the anti-recirculation feature is about 550-600 mm.
 15. The engine grill of claim 13, wherein: the end portion includes: a generally planar first portion; and a generally planar second portion tilted away from the first portion; and the disc-shaped solid member extends at least partway across the first and second portions.
 16. The engine grill of claim 15, wherein the engine grill includes a plurality of transverse corrugations that extend across the anti-recirculation feature.
 17. A power unit, comprising: an engine disposed within an engine housing; a heat exchanger fluidly connected to the engine and disposed within the engine housing at one end of the engine; a fan disposed within the engine housing adjacent the heat exchanger and configured to generate a flow of air through the heat exchanger; an engine grill disposed adjacent the fan and having: an end portion; a plurality of perforations formed within the end portion in a pattern around a middle of the end portion and configured to allow passage of the flow of air generated by the fan; and disc-shaped solid member situated at the middle of the end portion within the pattern of the plurality of perforations and configured to block the flow of air at a center of the fan and allow air to flow at a periphery of the fan; and an engine cowling configured to at least partially close off the engine housing and connect the engine grill to the fan.
 18. The power unit of claim 17, wherein the engine housing includes a plurality of air inlets configured to direct air to the fan.
 19. The power unit of claim 18, wherein the fan is configured to draw air from the plurality of air inlets through the heat exchanger and push the air around the disc-shaped solid member and out of the engine housing through the plurality of perforations.
 20. The power unit of claim 19, wherein an outer diameter of the disc-shaped solid member is about 60-80% of an outer diameter of the fan. 